Ah, just noticed you decided on a 12" GSO in the end......or have I just thrown the cat amongst the pigeons in your head again
Hey, why not get an LB 16, do what I am going to do, then when the savings recover get a servocat/argo goto system for it. Do some boundary layer fan mods and you've got a DSO and planet killer.
Put it this way. I only ever saw the planets as white discs with some grey detail with my 12". ie White Jupiter with 2 dark grey bands and on occasion some fainter grey detail, White Saturn and rings with some faint grey cloudbands, White Mars with some faint grey features like Syrtis major. I always wonder how anyone was seeing the White polar caps on a white disc!!
Anyway, although the 16" was a noticable but not huge jump with regard to DSO's, it seems it crossed a threashold for me seeing colour in the planets. Salmon Mars with white Polar caps!. Creamy Saturn and creamy Jupiter with brown bands etc.
For me, the apeture jump to 16" was as much about managability as anything else. I could fit the 16" truss broken down in my car where I couldn't fit my solid tube 12".